Eye of Horus

OK so this post isn’t really about the eye of Horus, which is an Egyptian symbol of protection and good health. It’s about the sclerotic ring of birds, a mummified bird in this case. In collaboration with Rozenn Bailleul-LeSuer of the Oriental Institute, Dr. Charles Pelizzari in Radiation & Cellular Oncology at the University of Chicago, and Dr. Christian Wietholt of Visage, Inc., Rozenn wanted to identify the mummy bird without taking its wrappings off. Since some human mummies have been imaged with x-ray computed tomography (CT), she brought the bird for me to image with our microCT. The images below have voxel size of about 150 microns. Although some clinical scanners can achieve 200 microns, it is with a 1 mm slice thickness. Whereas the microCT used here is isotropic, i.e., 150 microns in all 3 directions.

Sclerotic Ring

The first image below clearly demonstrates the sclerotic ring, which is an array of overlapping bones around the eye. From the Wiki (http://goo.gl/3J4al) they are believed to have a role in supporting the eye, especially in animals whose eyes are not spherical, or which live underwater. You can read more about bird vision here (http://goo.gl/VgtLi). Not knowing bird anatomy, Dr. Pelizzari and eye speculated that the sclerotic ring might be some type of ornament or lead-based decoration. Rozenn explained that it was part of the birds anatomy, i.e., it is a sclerotic ring. The third image below from M. Hall, demonstrates how measuring the sclerotic ring can help identify the bird’s species. In the article several measurements are tabulated (http://goo.gl/lJZ7X). Rozenn and her colleagues believe our little mummy bird is a kestrel.

Medical Imaging

Last Sunday Rajini Rao and I discussed the Visible Human project (http://goo.gl/cv2xU). In my post I mentioned that the software and technology that was generated by the project is useful for more than just visualizing the data from the sliced humans. In this post I demonstrate with my pal Christian Wietholt how the same technology from the Visible Human project can be used to render the microCT data in a way that makes it easier to identify the bird species. Amira from Visage, Inc. was used by Christian Wietholt and me to segment the images so that we could strip away the CT bed it was imaged on and the tape used to hold it. The mummy linens were also segmented. Only then, the exquisite detail is visualized. The first video slices in a sagittal direction while the last video slices the bird in the coronal direction. These virtual slices are in stark contrast to the analog slices GE provided to emphasize the huge advantage medical imaging provides (http://goo.gl/hBdPH).

We imaged other mummified birds with a clinical scanner as they were too big for the microCT. Please come see the exhibit in October at the Oriental Institute at the University of Chicago. You’ll be able to see more videos and the actual mummies on display. More information will be added here when it becomes available or you can check their website: http://oi.uchicago.edu/

I leave you with Powerslave by Iron Maiden

Powerslave

Into the abyss I’ll fall, the Eye of Horus

Into the eyes of the night, watching me go

Green is the cat’s eye that glows, in this temple

Enter the risen Osiris, risen again.

Powerslave- Iron Maiden

Enjoy ScienceSunday curated by (Allison Sekuler , Robby Bowles ,and Rajini Rao )

#sciencesunday #scienceeveryday

Edit added two photographs of the mummy.